1. Field of the Invention
Embodiments relate to a small sized and inexpensive high-power zoom lens system and an imaging apparatus including the same.
2. Description of the Related Art
Recently, digital cameras or video cameras having solid state imaging devices, such as charge coupled devices (CCDs) and complementary metal oxide semiconductors (CMOSs), are becoming popular. Especially, due to demands for megapixel camera modules, inexpensive cameras with over 5 million pixels for providing high quality images are being released. Imaging optics apparatuses using CCDs or CMOSs, such as digital cameras or cameras of cellular phones, are being developed to be smaller, to be lighter, and have lower costs.
A retracting barrel of a camera, which expands to a predetermined position when an image is to be captured and collapses into the camera when an image is not to be captured, is widely used for size reduction. In a camera having a retracting barrel, it is necessary to minimize intervals between lenses when the barrel is retracted to reduce the thickness of the camera in order to improve portability. As a result, it is desired to reduce a number of lenses for size reduction. However, it is difficult to secure excellent optical performance in response to greater number of pixels when the number of lenses is reduced.
Therefore, a zoom lens including three lens groups is widely used to satisfy the requirements described above. An example of a zoom lens system having a variable magnification capable of 2× magnification or more (and including a small imaging lens system for use in capturing an image) may be a zoom lens system including a first lens group having a negative refractive power, a second lens group having a positive refractive power overall, and a third lens group having a positive refractive power, wherein the first through third lens groups are arranged sequentially from an object side and magnification is changed by adjusting intervals between each of the lens groups. However, it is difficult to fulfill size reduction and cost reduction simultaneously while being able to realize a high magnification index.